The present invention is generally directed to a drug delivery device and more particularly to a disposable infusion device. The present invention is still more particularly directed to such a device capable of delivering any liquid medicament such as, for example, insulin, and which further includes an assembly that precludes unintended dosing the liquid medicament.
Administration of insulin has traditionally been accomplished using a syringe. Recently, needle carrying pen-like devices have also been employed for this purpose. Both forms of insulin administration require the patients to stick themselves each time they inject insulin, often many times a day. Thus, these traditional forms of insulin administration have been a rather pervasive intrusion in the lives and routines of the patient's who have had to adopt and employ them.
More recently, insulin pumps attached by tubing to an infusion set mounted on the patient's skin have been developed as an alternative form of insulin administration. Such pumps may be controlled by a programmable remote electronic system employing short range radio communication between a control device and electronics that control the pump. While such a device may involve fewer needle sticks, it is expensive to manufacture and complex to operate and cumbersome and awkward to wear. The cost of such a device can be many times the daily expense of using a traditional injection means such as a syringe or an insulin pen. It also requires a significant amount of training to use the control device. Great care in programming the device is required because the pump generally carries several days' worth of insulin. Improper programming or otherwise operating the pump can result in an excessive amount of delivered insulin which can be very dangerous and even fatal.
Many patients are reluctant to wear a pump device because it is socially awkward. The user must generally have a noticeable device that is generally as large as a pager attached to the outside of the patients clothes and a catheter like tubing set running from the device to an infusion set located on the patient's body. Besides being obvious and perhaps embarrassing, wearing such a device can be a serious impediment to many activities such as swimming, bathing, athletic activities, and many activities such as sun bathing where portions of the patient's body are necessarily uncovered.
In view of the above, a more cost effective and simple device has finally been proposed whereby an injection system is discreetly attached directly to the skin of the patient. Thus, the device may be attached to the patient under the patient's clothing to deliver insulin into the patient by the manual pumping of small doses of insulin through a temporarily indwelling cannula that is made a part of the pump device. The cannula may be made a part of the drug delivery device before, during or after the attachment of the drug delivery device to the skin of the patient. The device may be made quite small and, when worn under the cloths, entirely unnoticeable in most social situations. It may still carry sufficient insulin to last a patient several days. It can be colored to blend naturally with the patient's skin color so as not to be noticeable when the patient's skin is exposed. As a result, insulin for several days may be carried by the patient discreetly, and conveniently applied in small dosages after only a single needle stick. For a more complete description of devices of this type, reference may be had to co-pending application Ser. No. 11/906,130, filed on Sep. 28, 2007 for DISPOSABLE INFUSION DEVICE WITH DUAL VALVE SYSTEM, which application is owned by the assignee of this application and hereby incorporated herein by reference in its entirety.
The manual pumping mechanism of such a device may be designed to avoid activation by unintentional contact. This may be accomplished, for example, by making it necessary to squeeze two buttons concurrently in different directions so that bumping into a wall, falling down, engaging in contact sports, or other activity of this nature would not accidentally activate the pump. For a more complete description of exemplary devices of this type, reference may be had to co-pending application Ser. No. 11/516,456, filed on Sep. 6, 2006 for DISPOSABLE INFUSION DEVICE WITH LINEAR PERISTALTIC PUMP, which application is owned by the assignee of this application and hereby incorporated herein by reference in its entirety. Further, the pumping mechanism might have at least two trigger type buttons where both a safety button and a pumping button need to be activated concurrently past a trigger point to activate. This safety feature would thus prevent a partial pumping. For a more complete description of such a device of this type, reference may be had to co-pending application Ser. No. 11/906,102, filed on Sep. 28, 2007 for DISPOSABLE INFUSION DEVICE WITH SNAP ACTION ACTUATION, which application is owned by the assignee of this application and hereby incorporated herein by reference in its entirety.
Such a device with such safety features, while appropriate and highly advantageous in most situations, without some locking mechanism that requires intentional intervention by another person such as a supervising adult, might pose a hazard for very young children and for adult patients that need supervision. A drug delivery device of the type described above, especially if loaded with several days supply of insulin, could potentially be dangerous or even life threatening if the child or person needing supervision could inadvertently provide medicament dosage to themselves by unintentionally activating the pump.
Small children are generally very dexterous in their ability to manipulate small mechanical objects. They naturally fidget with and manipulate small objects in their grasp, and would naturally do so with a small device attached to their body. However, the advantage of having the insulin readily available, avoiding multiple needle sticks, and having the infusion of the drug be simple and rapid, are especially important with such patients. Functionality associated with such a device preventing unintentional dosing activation without supervisory involvement would be highly desirable.
Likewise, where an adult, such as a mentally confused patient, requires the supervision of another person, such a mechanism may be important. Diabetes is more prevalent as age increases, and thus will impact many patients suffering from Alzheimer disease or dementia due to advanced age. Likewise, mental impairment is one of the unfortunate side effects that may accompany a prolonged struggle with the diabetic condition. Although mentally confused, such a patient might none the less be fully capable of the physical dexterity needed to accidentally or unintentionally operate the drug delivery device, and might not even be aware that they had done so. As is the case with very small children, such an activation of the drug delivery device could well be dangerous.
Hence, there is a need in the art for a wearable drug delivery device that includes means for precluding or preventing unintended dosing actuation of the device. Preferably, such a mechanism would securely lock the drug delivery device and require a person other than the patient, such as an adult or caretaker, to unlock and activate the device. Permitting such action by the other person easily and reliably would also be highly desirable. This present invention addresses these and other issues.